Flexible die-holder.



FREDERIG E. WELLS, 0F GREENFIELD, MASSACHUSETTS.

FLEXIBLE DIE-HOLDER.

Specification of Letters Patent.

Application filed April 3, 1913.

Patented Dec. 30, 1913.

Serial No. 758,597.

To all whom it may concern:

Be it known that I, FREnERIc E. WELLS, a citizen of the United States of America, residing at Greenfield, in the county of Franklin and State of Massachusetts, have invented new and useful Improvements in Flexible Die-Holders, of which the following is a specification.

This invention relates to improvements in die-holders.

The object of the invention is to provide a device for holding or mounting the threadforming tool or die, as it is called, so that the same may automatically yield or move slightly in any direction in case the axis of the die is not in alinement with the axis of the work on which a thread is to be formed. The present method of using a thread-forming die is to mount the same in a fixed support, as in the turret-head of a screw-cutting machine, and feed or move this head toward the work that is mounted on and rotated by the mechanism contained in the head stock of the screw-cutting machine. This method is objectionable for the reason that it often occurs that the axis of a piece of work on which a thread is to be cut is not in exact alinement with the axis of the die that is fixedly secured in the turret-head of the machine.

The present invention is designed to provide means for flexibly mounting the die in its holder, whereby it may readily and automatically yield or move in any direction a distance to compensate for the imperfect alinement of the axis of the die and work.

The device for flexibly mounting the die embodied in the present invention permits it to readily follow the stock in any direction or angle, whereby a better thread will be formed than in the present method of rigidly mounting the die.

Referring to the drawings forming a part of the present invention,-Figure 1 is a longitudinal sectional view, taken on the line 11 of Fig. 2, of the die and its holder and showing the loose pivotal support or mounting of the die, also the flexible or yielding device to permit the die to move about its pivotal mounting; Fig. 2 is a longitudinal sectional view taken on the line 22 of Fig. 1 through the axis of the die and its holder and at right angles to that shown in Fig. 1; and Fig. 3 is a top plan view showing in dotted lines the die after it has moved a slight distance axially of its supporting trunnions.

In detail, a designates the hollow shank portion which is formed with an opening I) therethrough to receive the work or stock on which a thread is to be cut. Formed integral with the shank a is a headmember 0 having two arm-members (Z and c. The thread-forming die is indicated at f and the collet-member in which the die is secured is indicated at g. The collet is also formed with an opening it which registers with the opening 5. The head 0 is formed with two ledge portions 11 and y'.

is designates a spring that is located between the lower edge m of the collet and the ledge portions 71 and This spring is formed with an opening 0 in line with the opening 6 in the shank and the opening it in the collectmember 9; also two smaller openings on opposite side of the opening 0 to receive the two pins 39 and g. The spring is is formed with a flat portion r which engages the underside m of the collet-member and oppositely extending foot portions 8 which engage the ledge portions 2' and j,- the portions 7" and 8 being connected by the inclined portions 6, all as clearly shown in the figures.

In order to loosely and pivotally support the collet-member, two oppositely-located pivotal supports u and 4) are threaded in the arm-members (Z and 6; their inner ends being turned down to form bearings which enter diametrically-located openings w and m in the collet-member. These openings, it will be noticed, are made larger than the turned-down portions y and e of the pivotal supports a and '22 so as to permit the colletmember to move upward by the action of the spring is pressing against the underside thereof; the loose connection between the portions g and z and the openings w and w being clearly indicated in Fig. 1. It should be observed also that the colletmember 9 can slightly move endwise on the the axis of the stock on which a thread is thread will be out than in the methods now employed, wherein the collet is retained in a fixed position. In fact, the collet and die can follow an elliptical path, if necessary, during the thread-forming operation.

hat I claim is, 1. A collet-mounting for a die comprising a a support therefor, of trunnions in the support and entering enlarged openings in the collet, means to normally move the collet to cause the trunnions to engage one side of the enlarged openings, whereby the die will automatically aline itself with the axis of the stock on which a thread is being formed.

2. In a mounting for a die, of means to permit the same to automatically move in any direction transverse to the axis of the die, said means comprising a loose trunnion connection bet-ween the collet in which the die is mounted and its supporting member, and a spring located between the collet and the supporting member to normally force the collet in an outward direction, as described.

3. A mounting for" a thread-forming member, comprising a support therefor, a collet to receive said member, trunnions in the support and entering enlarged openings in the collet, the support having ledges thereon, a spring engaging the ledges and the collet to force the latter against the trunnions, pins in the collet and arranged to enter openings formed in the spring to position the latter, the spring having a centrally located opening in alinement with the axis of the support, and the trunnions being formed to permit endwise movement of the collet on the trunnions, whereby the collet member may automatically yield in any direction transverse to the axis of the collet when a thread is being formed.

FREDERIC E. WELLS.

Witnesses ERNEST K. SUHL, JOSEPH G. STEVENS.

Copies of this patent may be obtained for five cents each, by addressing the c Commissioner or Batenzs Washington, 11.0. 

